WC-CoCr coatings sprayed by high velocity oxygen-fuel (HVOF) flame on AA7050 aluminum alloy: electrochemical behavior in 3.5% NaCl solution

Autor(es)

Marina Magnani ^[1] ; Patrícia Hatsue Suegama ^[2] ; Abel André Cândido Recco ^[3] ; Josep Maria Guilemany ^[4] ; Cecílio Sadao Fugivara ^[5] ; Assis Vicente Benedetti ^[6]

Afiliação do(s) autor(es)

^[1] Universidade Estadual Paulista. Instituto de Química - Brasil

^[2] Universidade Estadual Paulista. Instituto de Química - Brasil

^[3] Universidade de São Paulo. Escola Politécnica - Brasil

^[4] Universitat de Barcelona. Materials Engineering. CPT Thermal Spray Centre - Espanha

^[5] Universidade Estadual Paulista. Instituto de Química - Brasil

^[6] Universidade Estadual Paulista. Instituto de Química - Brasil

• Tipo de documento: Artigo Científico
• Fonte: MATERIALS RESEARCH-IBERO-AMERICAN JOURNAL OF MATERIALS; v. 10, n. 4, p. 377-385, 2007-12-00.

Resumo

In the present work, the electrochemical behavior of WC-CoCr coatings with 10 (W10), 15 (W15) and 20 (W20) torch passes sprayed by High Velocity Oxygen-Fuel (HVOF) flame on AA7050 aluminum alloy substrate, evaluated in 3.5% NaCl solution, were compared using open-circuit potential (E OC) measurements, electrochemical impedance spectroscopy (EIS) and polarization curves. The coating surfaces and their cross sections were characterized by X ray diffraction and the Rockwell-C hardness test, and also by optical (OM) and scanning electron microscopy (SEM) before and after the corrosion tests. The electrochemical data showed that sample W10 presented higher corrosion resistance than the others in chloride solutions. In some tests, aluminum salts on the coating surface were identified by EDS, indicating the corrosion of the substrate. And using aluminon, aluminum ions were detected and analyzing the surface via stereomicroscopy, hydrogen bubbles were observed, both showing that the electrolyte reached the substrate and galvanic corrosion possibly occurred. The physical characterization showed that sample W10 presented a lower number of cracks and pores, justifying its higher corrosion resistance. (AU)

• Processo FAPESP: 02/11542-4 - Caracterização da resistência à corrosão de revestimentos metálico-cerâmicos aplicados em ligas de alumínio mediante a técnica aspersão térmica a alta velocidade ( HVOF)
• Beneficiário: Marina Magnani
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 05/51851-4 - Nanocompósitos à base de polissilanos aditivados como pré-tratamentos protetores contra corrosão para aço carbono
• Beneficiário: Patricia Hatsue Suegama
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 04/00776-0 - Caracterizacao tribologica de filmes da tin/ti depositados em aco inoxidavel aisi 316 por pvd triodo magnetron sputtering.
• Beneficiário: Abel Andre Cândido Recco
• Modalidade de apoio: Bolsas no Brasil - Doutorado